include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit...
[linux-2.6.git] / fs / nfsd / nfs4callback.c
1 /*
2  *  Copyright (c) 2001 The Regents of the University of Michigan.
3  *  All rights reserved.
4  *
5  *  Kendrick Smith <kmsmith@umich.edu>
6  *  Andy Adamson <andros@umich.edu>
7  *
8  *  Redistribution and use in source and binary forms, with or without
9  *  modification, are permitted provided that the following conditions
10  *  are met:
11  *
12  *  1. Redistributions of source code must retain the above copyright
13  *     notice, this list of conditions and the following disclaimer.
14  *  2. Redistributions in binary form must reproduce the above copyright
15  *     notice, this list of conditions and the following disclaimer in the
16  *     documentation and/or other materials provided with the distribution.
17  *  3. Neither the name of the University nor the names of its
18  *     contributors may be used to endorse or promote products derived
19  *     from this software without specific prior written permission.
20  *
21  *  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
22  *  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
23  *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
24  *  DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  *  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
26  *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
27  *  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
28  *  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
29  *  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
30  *  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
31  *  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32  */
33
34 #include <linux/sunrpc/clnt.h>
35 #include <linux/slab.h>
36 #include "nfsd.h"
37 #include "state.h"
38
39 #define NFSDDBG_FACILITY                NFSDDBG_PROC
40
41 #define NFSPROC4_CB_NULL 0
42 #define NFSPROC4_CB_COMPOUND 1
43 #define NFS4_STATEID_SIZE 16
44
45 /* Index of predefined Linux callback client operations */
46
47 enum {
48         NFSPROC4_CLNT_CB_NULL = 0,
49         NFSPROC4_CLNT_CB_RECALL,
50         NFSPROC4_CLNT_CB_SEQUENCE,
51 };
52
53 enum nfs_cb_opnum4 {
54         OP_CB_RECALL            = 4,
55         OP_CB_SEQUENCE          = 11,
56 };
57
58 #define NFS4_MAXTAGLEN          20
59
60 #define NFS4_enc_cb_null_sz             0
61 #define NFS4_dec_cb_null_sz             0
62 #define cb_compound_enc_hdr_sz          4
63 #define cb_compound_dec_hdr_sz          (3 + (NFS4_MAXTAGLEN >> 2))
64 #define sessionid_sz                    (NFS4_MAX_SESSIONID_LEN >> 2)
65 #define cb_sequence_enc_sz              (sessionid_sz + 4 +             \
66                                         1 /* no referring calls list yet */)
67 #define cb_sequence_dec_sz              (op_dec_sz + sessionid_sz + 4)
68
69 #define op_enc_sz                       1
70 #define op_dec_sz                       2
71 #define enc_nfs4_fh_sz                  (1 + (NFS4_FHSIZE >> 2))
72 #define enc_stateid_sz                  (NFS4_STATEID_SIZE >> 2)
73 #define NFS4_enc_cb_recall_sz           (cb_compound_enc_hdr_sz +       \
74                                         cb_sequence_enc_sz +            \
75                                         1 + enc_stateid_sz +            \
76                                         enc_nfs4_fh_sz)
77
78 #define NFS4_dec_cb_recall_sz           (cb_compound_dec_hdr_sz  +      \
79                                         cb_sequence_dec_sz +            \
80                                         op_dec_sz)
81
82 struct nfs4_rpc_args {
83         void                            *args_op;
84         struct nfsd4_cb_sequence        args_seq;
85 };
86
87 /*
88 * Generic encode routines from fs/nfs/nfs4xdr.c
89 */
90 static inline __be32 *
91 xdr_writemem(__be32 *p, const void *ptr, int nbytes)
92 {
93         int tmp = XDR_QUADLEN(nbytes);
94         if (!tmp)
95                 return p;
96         p[tmp-1] = 0;
97         memcpy(p, ptr, nbytes);
98         return p + tmp;
99 }
100
101 #define WRITE32(n)               *p++ = htonl(n)
102 #define WRITEMEM(ptr,nbytes)     do {                           \
103         p = xdr_writemem(p, ptr, nbytes);                       \
104 } while (0)
105 #define RESERVE_SPACE(nbytes)   do {                            \
106         p = xdr_reserve_space(xdr, nbytes);                     \
107         if (!p) dprintk("NFSD: RESERVE_SPACE(%d) failed in function %s\n", (int) (nbytes), __func__); \
108         BUG_ON(!p);                                             \
109 } while (0)
110
111 /*
112  * Generic decode routines from fs/nfs/nfs4xdr.c
113  */
114 #define DECODE_TAIL                             \
115         status = 0;                             \
116 out:                                            \
117         return status;                          \
118 xdr_error:                                      \
119         dprintk("NFSD: xdr error! (%s:%d)\n", __FILE__, __LINE__); \
120         status = -EIO;                          \
121         goto out
122
123 #define READ32(x)         (x) = ntohl(*p++)
124 #define READ64(x)         do {                  \
125         (x) = (u64)ntohl(*p++) << 32;           \
126         (x) |= ntohl(*p++);                     \
127 } while (0)
128 #define READTIME(x)       do {                  \
129         p++;                                    \
130         (x.tv_sec) = ntohl(*p++);               \
131         (x.tv_nsec) = ntohl(*p++);              \
132 } while (0)
133 #define READ_BUF(nbytes)  do { \
134         p = xdr_inline_decode(xdr, nbytes); \
135         if (!p) { \
136                 dprintk("NFSD: %s: reply buffer overflowed in line %d.\n", \
137                         __func__, __LINE__); \
138                 return -EIO; \
139         } \
140 } while (0)
141
142 struct nfs4_cb_compound_hdr {
143         /* args */
144         u32             ident;  /* minorversion 0 only */
145         u32             nops;
146         __be32          *nops_p;
147         u32             minorversion;
148         /* res */
149         int             status;
150         u32             taglen;
151         char            *tag;
152 };
153
154 static struct {
155 int stat;
156 int errno;
157 } nfs_cb_errtbl[] = {
158         { NFS4_OK,              0               },
159         { NFS4ERR_PERM,         EPERM           },
160         { NFS4ERR_NOENT,        ENOENT          },
161         { NFS4ERR_IO,           EIO             },
162         { NFS4ERR_NXIO,         ENXIO           },
163         { NFS4ERR_ACCESS,       EACCES          },
164         { NFS4ERR_EXIST,        EEXIST          },
165         { NFS4ERR_XDEV,         EXDEV           },
166         { NFS4ERR_NOTDIR,       ENOTDIR         },
167         { NFS4ERR_ISDIR,        EISDIR          },
168         { NFS4ERR_INVAL,        EINVAL          },
169         { NFS4ERR_FBIG,         EFBIG           },
170         { NFS4ERR_NOSPC,        ENOSPC          },
171         { NFS4ERR_ROFS,         EROFS           },
172         { NFS4ERR_MLINK,        EMLINK          },
173         { NFS4ERR_NAMETOOLONG,  ENAMETOOLONG    },
174         { NFS4ERR_NOTEMPTY,     ENOTEMPTY       },
175         { NFS4ERR_DQUOT,        EDQUOT          },
176         { NFS4ERR_STALE,        ESTALE          },
177         { NFS4ERR_BADHANDLE,    EBADHANDLE      },
178         { NFS4ERR_BAD_COOKIE,   EBADCOOKIE      },
179         { NFS4ERR_NOTSUPP,      ENOTSUPP        },
180         { NFS4ERR_TOOSMALL,     ETOOSMALL       },
181         { NFS4ERR_SERVERFAULT,  ESERVERFAULT    },
182         { NFS4ERR_BADTYPE,      EBADTYPE        },
183         { NFS4ERR_LOCKED,       EAGAIN          },
184         { NFS4ERR_RESOURCE,     EREMOTEIO       },
185         { NFS4ERR_SYMLINK,      ELOOP           },
186         { NFS4ERR_OP_ILLEGAL,   EOPNOTSUPP      },
187         { NFS4ERR_DEADLOCK,     EDEADLK         },
188         { -1,                   EIO             }
189 };
190
191 static int
192 nfs_cb_stat_to_errno(int stat)
193 {
194         int i;
195         for (i = 0; nfs_cb_errtbl[i].stat != -1; i++) {
196                 if (nfs_cb_errtbl[i].stat == stat)
197                         return nfs_cb_errtbl[i].errno;
198         }
199         /* If we cannot translate the error, the recovery routines should
200         * handle it.
201         * Note: remaining NFSv4 error codes have values > 10000, so should
202         * not conflict with native Linux error codes.
203         */
204         return stat;
205 }
206
207 /*
208  * XDR encode
209  */
210
211 static void
212 encode_cb_compound_hdr(struct xdr_stream *xdr, struct nfs4_cb_compound_hdr *hdr)
213 {
214         __be32 * p;
215
216         RESERVE_SPACE(16);
217         WRITE32(0);            /* tag length is always 0 */
218         WRITE32(hdr->minorversion);
219         WRITE32(hdr->ident);
220         hdr->nops_p = p;
221         WRITE32(hdr->nops);
222 }
223
224 static void encode_cb_nops(struct nfs4_cb_compound_hdr *hdr)
225 {
226         *hdr->nops_p = htonl(hdr->nops);
227 }
228
229 static void
230 encode_cb_recall(struct xdr_stream *xdr, struct nfs4_delegation *dp,
231                 struct nfs4_cb_compound_hdr *hdr)
232 {
233         __be32 *p;
234         int len = dp->dl_fh.fh_size;
235
236         RESERVE_SPACE(12+sizeof(dp->dl_stateid) + len);
237         WRITE32(OP_CB_RECALL);
238         WRITE32(dp->dl_stateid.si_generation);
239         WRITEMEM(&dp->dl_stateid.si_opaque, sizeof(stateid_opaque_t));
240         WRITE32(0); /* truncate optimization not implemented */
241         WRITE32(len);
242         WRITEMEM(&dp->dl_fh.fh_base, len);
243         hdr->nops++;
244 }
245
246 static void
247 encode_cb_sequence(struct xdr_stream *xdr, struct nfsd4_cb_sequence *args,
248                    struct nfs4_cb_compound_hdr *hdr)
249 {
250         __be32 *p;
251
252         if (hdr->minorversion == 0)
253                 return;
254
255         RESERVE_SPACE(1 + NFS4_MAX_SESSIONID_LEN + 20);
256
257         WRITE32(OP_CB_SEQUENCE);
258         WRITEMEM(args->cbs_clp->cl_sessionid.data, NFS4_MAX_SESSIONID_LEN);
259         WRITE32(args->cbs_clp->cl_cb_seq_nr);
260         WRITE32(0);             /* slotid, always 0 */
261         WRITE32(0);             /* highest slotid always 0 */
262         WRITE32(0);             /* cachethis always 0 */
263         WRITE32(0); /* FIXME: support referring_call_lists */
264         hdr->nops++;
265 }
266
267 static int
268 nfs4_xdr_enc_cb_null(struct rpc_rqst *req, __be32 *p)
269 {
270         struct xdr_stream xdrs, *xdr = &xdrs;
271
272         xdr_init_encode(&xdrs, &req->rq_snd_buf, p);
273         RESERVE_SPACE(0);
274         return 0;
275 }
276
277 static int
278 nfs4_xdr_enc_cb_recall(struct rpc_rqst *req, __be32 *p,
279                 struct nfs4_rpc_args *rpc_args)
280 {
281         struct xdr_stream xdr;
282         struct nfs4_delegation *args = rpc_args->args_op;
283         struct nfs4_cb_compound_hdr hdr = {
284                 .ident = args->dl_ident,
285                 .minorversion = rpc_args->args_seq.cbs_minorversion,
286         };
287
288         xdr_init_encode(&xdr, &req->rq_snd_buf, p);
289         encode_cb_compound_hdr(&xdr, &hdr);
290         encode_cb_sequence(&xdr, &rpc_args->args_seq, &hdr);
291         encode_cb_recall(&xdr, args, &hdr);
292         encode_cb_nops(&hdr);
293         return 0;
294 }
295
296
297 static int
298 decode_cb_compound_hdr(struct xdr_stream *xdr, struct nfs4_cb_compound_hdr *hdr){
299         __be32 *p;
300
301         READ_BUF(8);
302         READ32(hdr->status);
303         READ32(hdr->taglen);
304         READ_BUF(hdr->taglen + 4);
305         hdr->tag = (char *)p;
306         p += XDR_QUADLEN(hdr->taglen);
307         READ32(hdr->nops);
308         return 0;
309 }
310
311 static int
312 decode_cb_op_hdr(struct xdr_stream *xdr, enum nfs_opnum4 expected)
313 {
314         __be32 *p;
315         u32 op;
316         int32_t nfserr;
317
318         READ_BUF(8);
319         READ32(op);
320         if (op != expected) {
321                 dprintk("NFSD: decode_cb_op_hdr: Callback server returned "
322                          " operation %d but we issued a request for %d\n",
323                          op, expected);
324                 return -EIO;
325         }
326         READ32(nfserr);
327         if (nfserr != NFS_OK)
328                 return -nfs_cb_stat_to_errno(nfserr);
329         return 0;
330 }
331
332 /*
333  * Our current back channel implmentation supports a single backchannel
334  * with a single slot.
335  */
336 static int
337 decode_cb_sequence(struct xdr_stream *xdr, struct nfsd4_cb_sequence *res,
338                    struct rpc_rqst *rqstp)
339 {
340         struct nfs4_sessionid id;
341         int status;
342         u32 dummy;
343         __be32 *p;
344
345         if (res->cbs_minorversion == 0)
346                 return 0;
347
348         status = decode_cb_op_hdr(xdr, OP_CB_SEQUENCE);
349         if (status)
350                 return status;
351
352         /*
353          * If the server returns different values for sessionID, slotID or
354          * sequence number, the server is looney tunes.
355          */
356         status = -ESERVERFAULT;
357
358         READ_BUF(NFS4_MAX_SESSIONID_LEN + 16);
359         memcpy(id.data, p, NFS4_MAX_SESSIONID_LEN);
360         p += XDR_QUADLEN(NFS4_MAX_SESSIONID_LEN);
361         if (memcmp(id.data, res->cbs_clp->cl_sessionid.data,
362                    NFS4_MAX_SESSIONID_LEN)) {
363                 dprintk("%s Invalid session id\n", __func__);
364                 goto out;
365         }
366         READ32(dummy);
367         if (dummy != res->cbs_clp->cl_cb_seq_nr) {
368                 dprintk("%s Invalid sequence number\n", __func__);
369                 goto out;
370         }
371         READ32(dummy);  /* slotid must be 0 */
372         if (dummy != 0) {
373                 dprintk("%s Invalid slotid\n", __func__);
374                 goto out;
375         }
376         /* FIXME: process highest slotid and target highest slotid */
377         status = 0;
378 out:
379         return status;
380 }
381
382
383 static int
384 nfs4_xdr_dec_cb_null(struct rpc_rqst *req, __be32 *p)
385 {
386         return 0;
387 }
388
389 static int
390 nfs4_xdr_dec_cb_recall(struct rpc_rqst *rqstp, __be32 *p,
391                 struct nfsd4_cb_sequence *seq)
392 {
393         struct xdr_stream xdr;
394         struct nfs4_cb_compound_hdr hdr;
395         int status;
396
397         xdr_init_decode(&xdr, &rqstp->rq_rcv_buf, p);
398         status = decode_cb_compound_hdr(&xdr, &hdr);
399         if (status)
400                 goto out;
401         if (seq) {
402                 status = decode_cb_sequence(&xdr, seq, rqstp);
403                 if (status)
404                         goto out;
405         }
406         status = decode_cb_op_hdr(&xdr, OP_CB_RECALL);
407 out:
408         return status;
409 }
410
411 /*
412  * RPC procedure tables
413  */
414 #define PROC(proc, call, argtype, restype)                              \
415 [NFSPROC4_CLNT_##proc] = {                                              \
416         .p_proc   = NFSPROC4_CB_##call,                                 \
417         .p_encode = (kxdrproc_t) nfs4_xdr_##argtype,                    \
418         .p_decode = (kxdrproc_t) nfs4_xdr_##restype,                    \
419         .p_arglen = NFS4_##argtype##_sz,                                \
420         .p_replen = NFS4_##restype##_sz,                                \
421         .p_statidx = NFSPROC4_CB_##call,                                \
422         .p_name   = #proc,                                              \
423 }
424
425 static struct rpc_procinfo     nfs4_cb_procedures[] = {
426     PROC(CB_NULL,      NULL,     enc_cb_null,     dec_cb_null),
427     PROC(CB_RECALL,    COMPOUND,   enc_cb_recall,      dec_cb_recall),
428 };
429
430 static struct rpc_version       nfs_cb_version4 = {
431         .number                 = 1,
432         .nrprocs                = ARRAY_SIZE(nfs4_cb_procedures),
433         .procs                  = nfs4_cb_procedures
434 };
435
436 static struct rpc_version *     nfs_cb_version[] = {
437         NULL,
438         &nfs_cb_version4,
439 };
440
441 static struct rpc_program cb_program;
442
443 static struct rpc_stat cb_stats = {
444                 .program        = &cb_program
445 };
446
447 #define NFS4_CALLBACK 0x40000000
448 static struct rpc_program cb_program = {
449                 .name           = "nfs4_cb",
450                 .number         = NFS4_CALLBACK,
451                 .nrvers         = ARRAY_SIZE(nfs_cb_version),
452                 .version        = nfs_cb_version,
453                 .stats          = &cb_stats,
454                 .pipe_dir_name  = "/nfsd4_cb",
455 };
456
457 static int max_cb_time(void)
458 {
459         return max(NFSD_LEASE_TIME/10, (time_t)1) * HZ;
460 }
461
462 /* Reference counting, callback cleanup, etc., all look racy as heck.
463  * And why is cb_set an atomic? */
464
465 int setup_callback_client(struct nfs4_client *clp)
466 {
467         struct nfs4_cb_conn *cb = &clp->cl_cb_conn;
468         struct rpc_timeout      timeparms = {
469                 .to_initval     = max_cb_time(),
470                 .to_retries     = 0,
471         };
472         struct rpc_create_args args = {
473                 .protocol       = XPRT_TRANSPORT_TCP,
474                 .address        = (struct sockaddr *) &cb->cb_addr,
475                 .addrsize       = cb->cb_addrlen,
476                 .timeout        = &timeparms,
477                 .program        = &cb_program,
478                 .prognumber     = cb->cb_prog,
479                 .version        = nfs_cb_version[1]->number,
480                 .authflavor     = clp->cl_flavor,
481                 .flags          = (RPC_CLNT_CREATE_NOPING | RPC_CLNT_CREATE_QUIET),
482                 .client_name    = clp->cl_principal,
483         };
484         struct rpc_clnt *client;
485
486         if (!clp->cl_principal && (clp->cl_flavor >= RPC_AUTH_GSS_KRB5))
487                 return -EINVAL;
488         if (cb->cb_minorversion) {
489                 args.bc_xprt = clp->cl_cb_xprt;
490                 args.protocol = XPRT_TRANSPORT_BC_TCP;
491         }
492         /* Create RPC client */
493         client = rpc_create(&args);
494         if (IS_ERR(client)) {
495                 dprintk("NFSD: couldn't create callback client: %ld\n",
496                         PTR_ERR(client));
497                 return PTR_ERR(client);
498         }
499         cb->cb_client = client;
500         return 0;
501
502 }
503
504 static void warn_no_callback_path(struct nfs4_client *clp, int reason)
505 {
506         dprintk("NFSD: warning: no callback path to client %.*s: error %d\n",
507                 (int)clp->cl_name.len, clp->cl_name.data, reason);
508 }
509
510 static void nfsd4_cb_probe_done(struct rpc_task *task, void *calldata)
511 {
512         struct nfs4_client *clp = calldata;
513
514         if (task->tk_status)
515                 warn_no_callback_path(clp, task->tk_status);
516         else
517                 atomic_set(&clp->cl_cb_conn.cb_set, 1);
518         put_nfs4_client(clp);
519 }
520
521 static const struct rpc_call_ops nfsd4_cb_probe_ops = {
522         .rpc_call_done = nfsd4_cb_probe_done,
523 };
524
525 static struct rpc_cred *callback_cred;
526
527 int set_callback_cred(void)
528 {
529         if (callback_cred)
530                 return 0;
531         callback_cred = rpc_lookup_machine_cred();
532         if (!callback_cred)
533                 return -ENOMEM;
534         return 0;
535 }
536
537
538 void do_probe_callback(struct nfs4_client *clp)
539 {
540         struct nfs4_cb_conn *cb = &clp->cl_cb_conn;
541         struct rpc_message msg = {
542                 .rpc_proc       = &nfs4_cb_procedures[NFSPROC4_CLNT_CB_NULL],
543                 .rpc_argp       = clp,
544                 .rpc_cred       = callback_cred
545         };
546         int status;
547
548         status = rpc_call_async(cb->cb_client, &msg,
549                                 RPC_TASK_SOFT | RPC_TASK_SOFTCONN,
550                                 &nfsd4_cb_probe_ops, (void *)clp);
551         if (status) {
552                 warn_no_callback_path(clp, status);
553                 put_nfs4_client(clp);
554         }
555 }
556
557 /*
558  * Set up the callback client and put a NFSPROC4_CB_NULL on the wire...
559  */
560 void
561 nfsd4_probe_callback(struct nfs4_client *clp)
562 {
563         int status;
564
565         BUG_ON(atomic_read(&clp->cl_cb_conn.cb_set));
566
567         status = setup_callback_client(clp);
568         if (status) {
569                 warn_no_callback_path(clp, status);
570                 return;
571         }
572
573         /* the task holds a reference to the nfs4_client struct */
574         atomic_inc(&clp->cl_count);
575
576         do_probe_callback(clp);
577 }
578
579 /*
580  * There's currently a single callback channel slot.
581  * If the slot is available, then mark it busy.  Otherwise, set the
582  * thread for sleeping on the callback RPC wait queue.
583  */
584 static int nfsd41_cb_setup_sequence(struct nfs4_client *clp,
585                 struct rpc_task *task)
586 {
587         struct nfs4_rpc_args *args = task->tk_msg.rpc_argp;
588         u32 *ptr = (u32 *)clp->cl_sessionid.data;
589         int status = 0;
590
591         dprintk("%s: %u:%u:%u:%u\n", __func__,
592                 ptr[0], ptr[1], ptr[2], ptr[3]);
593
594         if (test_and_set_bit(0, &clp->cl_cb_slot_busy) != 0) {
595                 rpc_sleep_on(&clp->cl_cb_waitq, task, NULL);
596                 dprintk("%s slot is busy\n", __func__);
597                 status = -EAGAIN;
598                 goto out;
599         }
600
601         /*
602          * We'll need the clp during XDR encoding and decoding,
603          * and the sequence during decoding to verify the reply
604          */
605         args->args_seq.cbs_clp = clp;
606         task->tk_msg.rpc_resp = &args->args_seq;
607
608 out:
609         dprintk("%s status=%d\n", __func__, status);
610         return status;
611 }
612
613 /*
614  * TODO: cb_sequence should support referring call lists, cachethis, multiple
615  * slots, and mark callback channel down on communication errors.
616  */
617 static void nfsd4_cb_prepare(struct rpc_task *task, void *calldata)
618 {
619         struct nfs4_delegation *dp = calldata;
620         struct nfs4_client *clp = dp->dl_client;
621         struct nfs4_rpc_args *args = task->tk_msg.rpc_argp;
622         u32 minorversion = clp->cl_cb_conn.cb_minorversion;
623         int status = 0;
624
625         args->args_seq.cbs_minorversion = minorversion;
626         if (minorversion) {
627                 status = nfsd41_cb_setup_sequence(clp, task);
628                 if (status) {
629                         if (status != -EAGAIN) {
630                                 /* terminate rpc task */
631                                 task->tk_status = status;
632                                 task->tk_action = NULL;
633                         }
634                         return;
635                 }
636         }
637         rpc_call_start(task);
638 }
639
640 static void nfsd4_cb_done(struct rpc_task *task, void *calldata)
641 {
642         struct nfs4_delegation *dp = calldata;
643         struct nfs4_client *clp = dp->dl_client;
644
645         dprintk("%s: minorversion=%d\n", __func__,
646                 clp->cl_cb_conn.cb_minorversion);
647
648         if (clp->cl_cb_conn.cb_minorversion) {
649                 /* No need for lock, access serialized in nfsd4_cb_prepare */
650                 ++clp->cl_cb_seq_nr;
651                 clear_bit(0, &clp->cl_cb_slot_busy);
652                 rpc_wake_up_next(&clp->cl_cb_waitq);
653                 dprintk("%s: freed slot, new seqid=%d\n", __func__,
654                         clp->cl_cb_seq_nr);
655
656                 /* We're done looking into the sequence information */
657                 task->tk_msg.rpc_resp = NULL;
658         }
659 }
660
661 static void nfsd4_cb_recall_done(struct rpc_task *task, void *calldata)
662 {
663         struct nfs4_delegation *dp = calldata;
664         struct nfs4_client *clp = dp->dl_client;
665
666         nfsd4_cb_done(task, calldata);
667
668         switch (task->tk_status) {
669         case -EIO:
670                 /* Network partition? */
671                 atomic_set(&clp->cl_cb_conn.cb_set, 0);
672                 warn_no_callback_path(clp, task->tk_status);
673         case -EBADHANDLE:
674         case -NFS4ERR_BAD_STATEID:
675                 /* Race: client probably got cb_recall
676                  * before open reply granting delegation */
677                 break;
678         default:
679                 /* success, or error we can't handle */
680                 goto done;
681         }
682         if (dp->dl_retries--) {
683                 rpc_delay(task, 2*HZ);
684                 task->tk_status = 0;
685                 rpc_restart_call(task);
686                 return;
687         } else {
688                 atomic_set(&clp->cl_cb_conn.cb_set, 0);
689                 warn_no_callback_path(clp, task->tk_status);
690         }
691 done:
692         kfree(task->tk_msg.rpc_argp);
693 }
694
695 static void nfsd4_cb_recall_release(void *calldata)
696 {
697         struct nfs4_delegation *dp = calldata;
698         struct nfs4_client *clp = dp->dl_client;
699
700         nfs4_put_delegation(dp);
701         put_nfs4_client(clp);
702 }
703
704 static const struct rpc_call_ops nfsd4_cb_recall_ops = {
705         .rpc_call_prepare = nfsd4_cb_prepare,
706         .rpc_call_done = nfsd4_cb_recall_done,
707         .rpc_release = nfsd4_cb_recall_release,
708 };
709
710 /*
711  * called with dp->dl_count inc'ed.
712  */
713 void
714 nfsd4_cb_recall(struct nfs4_delegation *dp)
715 {
716         struct nfs4_client *clp = dp->dl_client;
717         struct rpc_clnt *clnt = clp->cl_cb_conn.cb_client;
718         struct nfs4_rpc_args *args;
719         struct rpc_message msg = {
720                 .rpc_proc = &nfs4_cb_procedures[NFSPROC4_CLNT_CB_RECALL],
721                 .rpc_cred = callback_cred
722         };
723         int status = -ENOMEM;
724
725         args = kzalloc(sizeof(*args), GFP_KERNEL);
726         if (!args)
727                 goto out;
728         args->args_op = dp;
729         msg.rpc_argp = args;
730         dp->dl_retries = 1;
731         status = rpc_call_async(clnt, &msg, RPC_TASK_SOFT,
732                                 &nfsd4_cb_recall_ops, dp);
733 out:
734         if (status) {
735                 kfree(args);
736                 put_nfs4_client(clp);
737                 nfs4_put_delegation(dp);
738         }
739 }